1. Field of the Invention
The present invention relates to a multi-sync display apparatus that selectively displays a plurality of types of image signals that have synchronization signals of respectively different frequencies. This application claims priority on Japanese Patent Application No. 2001-392348 the contents of which are incorporated herein by reference.
2. Description of the Related Art
Conventionally, in a multi-sync display apparatus that switches and selects a plurality of types of image signals having different synchronization signals output from a plurality of personal computers (PC), and displays one of these image signals, input synchronization signals are identified by detecting the frequency and polarity of synchronization signals input in synchronization with the image signals, and the display of the display apparatus is controlled in accordance with the identified synchronization signals.
In the method in which the display is controlled by detecting the frequency and polarity of the input synchronization signals, as described above, when the plurality of types of image signals are switched, if the synchronization signals before the switching are similar to the synchronization signals after the switching, then the problem has occurred that identifying the synchronization signals has not been possible, and therefore normal display control cannot be performed. In particular, in the case of a multi-sync type of display apparatus that uses a digital display apparatus such as a liquid crystal display, because it becomes impossible to perform a normal display if there is even a slight discrepancy in the synchronization signals, an extra burden has been placed on the user, for example, by requiring the user to perform manual adjustment and the like. If the frequency detection sensitivity when detecting input synchronization signals is raised as a means of dealing with this problem, the further problem arises that single lapses in synchronization and noise and the like are detected in error, resulting in a lowering in the detection accuracy.
The present invention was conceived in order to solve the above problems, and it is an object thereof to provide a multi-sync display apparatus that enables erroneous detections caused by lapses in synchronization and noise and the like to be prevented while increasing the accuracy with which similar input synchronization signals are identified.